1. Field of the Invention
Embodiments of the invention relate to a stereoscopic image display and a method for driving the same.
2. Discussion of the Related Art
A stereoscopic image display implements a three-dimensional (3D) image using a stereoscopic technique or an autostereoscopic technique. The stereoscopic technique, which uses a parallax image between left and right eyes of a user with a high stereoscopic effect, includes a glasses type method and a non-glasses type method, both of which have been put on the market. In the glasses type method, a stereoscopic image is implemented on a direct-view display or a projector using polarized glasses by varying a polarization direction of the parallax image between the left and right eyes. Alternatively, the stereoscopic image is implemented on the direct-view display or the projector using liquid crystal (LC) shutter glasses by displaying the parallax image between the left and right eyes in a time-division manner. In the non-glasses type method, an optical axis of the parallax image between the left and right eyes is generally separated using an optical plate such as a parallax barrier and a lenticular lens, and thus the stereoscopic image is implemented.
A lenticular lens type stereoscopic image display includes a lenticular lens positioned between a display panel and the user. The lenticular lens separates the left eye image and the right eye image to thereby implement the stereoscopic image. However, the lenticular lens type stereoscopic image display is at a disadvantage in being unable to turn on or off light separation. Thus, an LC lens type stereoscopic image display has been proposed to turn on or off the light separation in a 2D mode and a 3D mode by applying an electric field to liquid crystals.
FIG. 1 illustrates a portion of a 3-view LC lens type stereoscopic image display. As shown in FIG. 1, the LC lens type stereoscopic image display sets an optimum viewing distance based on the size of the stereoscopic image display and sets a focal length of a LC lens L based on a general distance (for example, about 65 mm) between both eyes, thereby implementing a stereoscopic image. In particular, views of the stereoscopic image are produced by separating cameras from one another by the general distance between both eyes and photographing images of an object. When the object is photographed using three cameras, the LC lens type stereoscopic image display shown in FIG. 1 may provide the stereoscopic image of three views. The LC lens type stereoscopic image display transmits light from a display panel through LC lens cells, thereby implementing the three view images having first to third viewpoints.
When both eyes of the user are positioned inside the first to third viewpoints, he or she may watch the optimum stereoscopic image. When both eyes of the user are positioned inside the first to third viewpoints, he/she is positioned inside an orthoscopic viewing region. The orthoscopic viewing region indicates that his/her right eye is positioned at the first viewpoint and his/her left eye is positioned at the second viewpoint, or that his/her right eye is positioned at the second viewpoint and his/her left eye is positioned at the third viewpoint. On the other hand, when his/her right eye is positioned at the third viewpoint and his/her left eye is positioned at the first viewpoint, he/she watches a left eye image through his/her right eye and watches a right eye image through his/her left eye. Thus, he/she watches not an orthoscopic image but a pseudoscopic image and may feel inconvenience in watching the pseudoscopic image. Further, when he/she watches the view images from different LC lenses L through both eyes, he/she may perceive that the view images are mixed.
When both eyes of the user are positioned at the optimum viewing distance, the user may watch an optimum stereoscopic image. However, when both eyes of the user are positioned out of the optimum distance and are positioned close to the LC lens cell or far away from the LC lens cell, the user is positioned in a pseudoscopic image viewing region or a mixed viewing region of the view images. Thus, the user may feel inconvenience in watching the stereoscopic image.